Five trillion pieces of plastic? That's almost 270,000 tons of plastic enough to fill over 38,500 garbage trucks and all of them are floating around in the world's oceans. Of course, marine life will be affected, but how?

In a study published in PLOS ONE, researchers not only outlined just how many pieces of plastic are polluting the world's waters but also explained how marine life is affected by all that trash, saying the biggest danger lies in entanglement and ingestion. Additionally, plastics are very good at absorbing pollutants so whatever a piece absorbs as it floats on the water will in turn be transferred to the fish, seabird or marine reptile that will be ingesting the plastic.

Researchers were able to approximate the number of plastics in the ocean through 24 expeditions across the Mediterranean Sea, Bay of Bengal, coastal Australia and all five sub-tropical gyres in the Indian Ocean, South Atlantic Ocean, South Pacific Ocean, North Atlantic Ocean and North Pacific Ocean from 2007 to 2013. In each expedition, visual surveys and surface net tows were employed to gather information, which then made it possible to create an oceanographic floating debris dispersal model responsible for the approximation.

In the past, estimates were limited to microplastics measuring less than 5mm. The model used by the study allowed for more extensive data because all size classes were sampled. The floating debris dispersal model also depended on three main variables: maritime activity, population density and watershed outfalls. Levels of pollution in plastics were also compared across size classes and between oceans. After empirical data was collected from 1,571 locations, the model was calibrated for accuracy.

By understanding just how much plastic is in the ocean, researchers in general should gain insight into the potential effects of the material on the environment and the food chain. For example, eating fish runs the risk of transferring the pollutants the fish may have absorbed by ingesting pieces of plastic in the ocean. Is it still safe to eat fish then considering the amount of plastics floating around?

Authors for the study include: Marcus Eriksen, Laurent C. M. Lebreton, Henry S. Carson, Martin Thiel, Charles Moore, Jose C. Borerro, Francois Galgani, Peter G. Ryan and Julia Reisser. Financial support was provided by the Will J. Reid Foundation, the Seaver Institute, Reisser's IPRS and CSIRO Flagship Postgraduate scholarship and Thiel's Chilean Millennium Initiative grant.